PL/SQL可搜索CASE語句

可搜索的CASE語句沒有選擇器，語句中的WHEN子句包含給出布爾值的搜索條件。

語法

PL/SQL中可搜索的case語句的語法是 -

CASE
   WHEN selector = 'value1' THEN S1;
   WHEN selector = 'value2' THEN S2;
   WHEN selector = 'value3' THEN S3;
   ...
   ELSE Sn;  -- default case
END CASE;

流程圖

實例

請參考以下示例代碼 -

SET SERVEROUTPUT ON SIZE 1000000;
DECLARE
   grade char(1) := 'B';
BEGIN
   case
      when grade = 'A' then dbms_output.put_line('Excellent');
      when grade = 'B' then dbms_output.put_line('Very good');
      when grade = 'C' then dbms_output.put_line('Well done');
      when grade = 'D' then dbms_output.put_line('You passed');
      when grade = 'F' then dbms_output.put_line('Better try again');
      else dbms_output.put_line('No such grade');
   end case;
END;
/

當上述代碼在SQL提示符下執行時，它會產生以下結果 -